I'm siding with Bobby on this one. In fact, I was going to post that along with my other post, but after getting started found it hard to get into words. I'm less medicated now.

I think the yeast, beer, and everything else is at an equal pressure, including the gas produced. So it makes sense that anything coming out of the walls of the yeast cells is in solution. It might even be this way for beer that is at normal pressure, and that Bubbles, or CO2 GAS, is only formed when several molecules of CO2 come together, when they then float to the surface of the fermenter as a gas (Having enough mass to create a large enough bubble to see and actually rise to the surface.)

I wonder if anyone makes a 1-wire pressure sensor that could be fitted into a bottle cap or some other vessel suitable for a small amount of pressure.

I remember something like that too. Can't remember who's video it was, but my guess is that Bobby's seen it too.
I don't really have anything to contribute other than I've always been under the impression that co2 does go into the headspace first (talking in ~room temp liquids) and then will dissolve into solution as temps are lowered. But, I've always been under this impression because of what I've read. What I've seen is that bottle or keg, chilling is what gets the perception of carbonation in the beer. I'd be really interested to see at what rates and temps the co2 actually dissolves into the liquid.

It seems to me from observation that carbonation absorbtion is linked to the temp of the fridge & the gravity of the beer. Lighter gravity can absorb co2 more quickly than a high gravity example. A pale ale may have great carbonation at one week fridge time. But my dark whiskely ale took 2 weeks fridge time to get decent head & carbonation.

Natural conditioning relies on residual yeast suspended in the beer that didn’t settle out during fermentation. The yeast consumes the priming sugar and releases carbon dioxide. Because the bottle or keg is capped, the carbon dioxide is not able to escape. Over time the trapped carbon dioxide dissolves into the beer, naturally carbonating it. Typically the carbonation process requires two to three weeks to complete.

Don't know if this is right or wrong. Just putting it out there.

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Normal dudes like you and I write the articles for BYO so they can easily repeat mistaken understandings in print. Think about this on the microscopic scale. Let's go back to the definition of carbonation; "Co2 molecules dissolved in an aqueous solution". Some CO2 reacts to H2O and becomes carbonic acid, but most of it just swims as single CO2 molecules. As yeast are releasing CO2, it's one molecule at a time. A single CO2 molecule in liquid is already considered dissolved. Because the source of CO2 in bottle conditioning is in the liquid already the liquid will always have the higher concentration of CO2 compared to the headspace until no more CO2 is being produced. At that point equilibrium is reached and the concentration will be equal.

I think people relate to the idea of the headspace being pressurized because of intermingling the concept of bottle conditioning with keg force carbing. That original experiment with the pressure gauge on the bottle was easy to mess up because of confirmation bias. The conclusion was inline with the preconception. Other than the temp impact that I was mostly concerned about, another reason that pressure could spike and drop later is deformation of the lid creating a small leak. Once the pressure dropped, the lid seal would be become effective again and level off. I'm not saying I know this happened, but it's another posibility.

Normal dudes like you and I write the articles for BYO so they can easily repeat mistaken understandings in print. Think about this on the microscopic scale. Let's go back to the definition of carbonation; "Co2 molecules dissolved in an aqueous solution". Some CO2 reacts to H2O and becomes carbonic acid, but most of it just swims as single CO2 molecules. As yeast are releasing CO2, it's one molecule at a time. A single CO2 molecule in liquid is already considered dissolved. Because the source of CO2 in bottle conditioning is in the liquid already the liquid will always have the higher concentration of CO2 compared to the headspace until no more CO2 is being produced. At that point equilibrium is reached and the concentration will be equal.

I think people relate to the idea of the headspace being pressurized because of intermingling the concept of bottle conditioning with keg force carbing. That original experiment with the pressure gauge on the bottle was easy to mess up because of confirmation bias. The conclusion was inline with the preconception. Other than the temp impact that I was mostly concerned about, another reason that pressure could spike and drop later is deformation of the lid creating a small leak. Once the pressure dropped, the lid seal would be become effective again and level off. I'm not saying I know this happened, but it's another posibility.

I'm totally onboard with this and is how I consider this happens. Boyle's Law, Charle's Law and all that good stuff...

That's it for me as well. MOST that I have done have been good after 7 days. This latest extract Summer Ale is taking much much longer though(I used regular table sugar as I was out of corn sugar). Weird thing was, to me, is that I brewed my all-grain Summer Ale the very next day and bottled them the same day and primed exactly the same and the all-grain was good at the 7 day mark.

Extract has been sitting for a few more weeks and now is much better. Both are still bottle aging but both are now good/awesome and ready at any time for the fridge. Guess I'll get on that after today's brew gets in the fermenters.

I'm totally onboard with this and is how I consider this happens. Boyle's Law, Charle's Law and all that good stuff...

So, Bolyle's law and Charle's law prove that the C02 from fermentation is absorbed into the wort at the same rate as it's produced? Knew that someone else must have done this work. I'm a blue collar guy and won't pretent to know or understand the science behind it, but it's already a proven fact, so there's no need to do this experiment. Thanks for the heads-up. Saved me some time.

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